Permeable surfacing options

Large elemental surfacing blocks

Precast concrete blocks with a pattern of voids intended for filling with soil, which allow for the growth of grass (grass concrete), laid on a recommended sub-base. These may remain relatively free-draining provided trafficking does not compact the earth fill within the void spaces. Typical uses are for low cost, temporary or occasional usage roadways and parking areas where vehicular loading is generally light and where the appearance of a grassed surface is seen as environmentally desirable, such as car parks, tram routes and fire access routes.

Small elemental surfacing blocks

Precast concrete blocks with a pattern of indentations along their edges intended to be filled with sharp sand/gravel, laid on a recommended sub-base, which should be single size crushed rock or other open-textured support. This remains free-draining provided surface maintenance limits the deposit of debris in the indentations and joints between blocks. Typical uses are for office and shopping centre car parks.

Continuous-laid permeable material

In-situ cast concrete systems are available that provide a surface with large voids for infiltration, whilst offering hard standing for vehicles. The surface is unsuitable for small-wheeled trolleys and pedestrian use over large areas and has limitations aesthetically. Typically used in car parking areas.